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| author | Josh Poimboeuf <jpoimboe@redhat.com> | 2021-01-29 00:52:19 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2021-02-10 11:29:21 +0300 |
| commit | 2a2dfe6a319afb47448b28bedd65319aa59faef0 (patch) | |
| tree | 87ca6d1bc42280507e463a84b3be68863a85b081 /arch/x86 | |
| parent | 032f8e04c0353f015d243008f039bb6e18a173c7 (diff) | |
| download | linux-2a2dfe6a319afb47448b28bedd65319aa59faef0.tar.xz | |
x86/build: Disable CET instrumentation in the kernel
commit 20bf2b378729c4a0366a53e2018a0b70ace94bcd upstream.
With retpolines disabled, some configurations of GCC, and specifically
the GCC versions 9 and 10 in Ubuntu will add Intel CET instrumentation
to the kernel by default. That breaks certain tracing scenarios by
adding a superfluous ENDBR64 instruction before the fentry call, for
functions which can be called indirectly.
CET instrumentation isn't currently necessary in the kernel, as CET is
only supported in user space. Disable it unconditionally and move it
into the x86's Makefile as CET/CFI... enablement should be a per-arch
decision anyway.
[ bp: Massage and extend commit message. ]
Fixes: 29be86d7f9cb ("kbuild: add -fcf-protection=none when using retpoline flags")
Reported-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Tested-by: Nikolay Borisov <nborisov@suse.com>
Cc: <stable@vger.kernel.org>
Cc: Seth Forshee <seth.forshee@canonical.com>
Cc: Masahiro Yamada <yamada.masahiro@socionext.com>
Link: https://lkml.kernel.org/r/20210128215219.6kct3h2eiustncws@treble
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'arch/x86')
| -rw-r--r-- | arch/x86/Makefile | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/arch/x86/Makefile b/arch/x86/Makefile index 1bf21746f4ce..6a7efa78eba2 100644 --- a/arch/x86/Makefile +++ b/arch/x86/Makefile @@ -127,6 +127,9 @@ else KBUILD_CFLAGS += -mno-red-zone KBUILD_CFLAGS += -mcmodel=kernel + + # Intel CET isn't enabled in the kernel + KBUILD_CFLAGS += $(call cc-option,-fcf-protection=none) endif ifdef CONFIG_X86_X32 |